Hydrophilic optical wmtening agents



FEESE United States Patent 3,048,584 HYDROPHILIC OPTICAL WHITENINGAGENTS OF THE STILBYL TRIAZOLE TYPE Dennis Arthur William Adams, Leeds,and Asim Kumar Sarkar, Adel, England, assignors to Hickson & WelchLimited, Castleford, England, a British company No Drawing. Filed Apr.15, 1960, Ser. No. 22,410 Claims priority, application Great BritainSept. 18, 1956 9 Claims. (Cl. 260240) This invention is concerned withimprovements in or relating to optical whitening agents and isparticularly concerned with certain new compounds for use as opticalwhitening agents. This application is a continuation-inpart of ourapplication Serial No. 683,702, filed September 13, 1957, now abandoned.

Optical whitening agents have in recent years found extensive use in thetreatment of textiles particularly during washing and are designed tocounteract the yellow or off-white colour which white textiles,particularly cellulosic textiles, may possess, especially after repeatedwashing. Such optical whitening agents also tend to improve colouredtextiles as they impart a general brightness to them. They are alsowidely used to impart whiteness to other cellulosic material,particularly paper.

Optical Whitening agents in general absorb light in the ultra-violetrange of the spectrum and emit in the visible spectrum, usually in thebluish-green to bluishviolet. Thus, the fluorescence of such compoundsin white material tends to counteract any yellowing as, for example,that resulting upon repeated washing of a white cotton or linen textile.The compounds used as optical whitening agents must be substantive tothe material being treated, and must be substantially stable when dyedon the material being treated.

In general best results are obtained with optical whitening agents whichgive a shade of fluorescence which is complementary to that of the agedfibre, so that the colours will cancel out each other. Since, ingeneral, the most common off-White shade of textiles resulting fromageing or repeated washing is yellow, the most desirable opticalwhitening agent is one that fluoresces blue.

It is also of importance that the optical whitening agent should not bedestroyed or removed by bleaching agents; that is, it should bebleach-fast. Thus, fluorescent optical whitening agents are generallyincorporated into soaps and synthetic detergents, which are marketed forhousehold use and articles washed therewith are often subjected tobleaching with various bleaching agents, for example sodiumhypochlorite. It is therefore desirable that the optical whiteningagents already on the fibre or in the treating solution should beaffected as little as possible by the action of any bleaching agentwhich may be present.

It is an object of the present invention to provide optical whiteningagents having improved properties in the foregoing respects.

We have now found that certain new compounds represented by the generalformula:

N X O H I in which X is a member of the group consisting of a hydrogenatom, a halogen atom and a lower alkoxy group and A is a group selectedfrom the group consisting of:

CROSS REYEYZENCE station-1 auuw:

3,048,584 Patented Aug. 7, 1962 in which R is a member selected from thegroup consisting of a hydrogen atom and a lower alkyl group andalkali-metal salts of these compounds, e.g. sodium salts can be usedwith advantage as optical whitening agents in that they possessfavourable properties from the point of view of the above-mentioneddesiderata for the ideal optical whitening agents.

Accordingly the invention comprises such compounds, together with theiralkali-metal, in particular sodium salts.

The compounds of the present invention show a good affinity forcellulosic material and exhibit a blue fluorescence, giving to the fibrea particularly pleasant hue. They show in general good resistance tobleaching agents and have good build-up qualities; that is-due towellbalanced substantivityon repeated treatments with a bath of the sameconcentration, the whiteness of the fabric being treated continuallyincreases up to a maximum, which maximum does not in general causeunpleasant visible colour or hue, as is often the case. In addition,those compounds in which the group A is ment of paper and photographicpaper where high whiteness is necessary.

According to a feature of the invention therefore there is provided acomposition having optical whitening propert-ies comprising a compoundof the formula:

(in which X and A have the above-stated meanings) and alkali-metal saltsthereof. The invention also includes cellulosic materials when treatedwith the above compositions, in particular cotton or linen textiles, andprotein and polyamide materials when treated with a compositioncontaining a compound in which the group A is Specific preferred newcompounds according to the invention are those set below together withtheir alkali metal salts.

2 (4" styryl 3 sulpho phenyl) (indazolo 6':7'- 4:5)-1:2:3-tn'azole.

2 (4" styryl 3" sulpho phenyl) (indazolo 4:5'- 4:5)-l:2:3-triazole.

2 (4" (4" methoxy styryl) 3" sulpho phenyl) (indazolo-6:7'-4: -1 :2:3-triazole.

2 (4 (4"' methoxy styryl) 3" sulpho phenyl) (indazolo-4 5-4 5 -1 :2:S-triazole.

2 (4" styryl 3" sulpho phenyl)(1' methyl indazolo-6:7-4:5)-l :2:3-triazole.

2 (4" styryl 3" sulpho phenyl) (3 methylindazolo-6':7'-4:5 -1 :23-triazole.

2 (4" styryl 3" sulpho phenyl) (1,3' dimethylindazolo-6 7'-4: 5 -1 2:3-triazole.

2(4" (4' chloro styryl) 3" sulpho phenyl) (indazole-6' 7-4: 5 -l 2:3-triazole.

2(4" (2" chlorostyryl) 3" sulpho phenyl) (indazole-6' 7'-4:5 -1 :2:3-triazole.

2(4" (4 chlorostyryl) 3" (indazolo-4:5-4: 5 -1 :2: 3-triazole.

2(4" (2" chlorostyryl) 3" sulpho phenyl) (indazolo-4 5 -4: 5 -1 :23-triazole.

A particularly preferred compound is 2-(4"-styryl-3"- sulpho phenyl)(indazolo-4':5-4:5 -1 :2z3-triazole.

In the above compounds the nomenclature adopted is based on thenumbering shown in the following formulae:

- sulpho phenyl) 3 III 2m The new compounds according to the inventioncan conveniently be prepared by oxidizing an o-amino azo dye of FormulaII given below, and according to a feature of the invention therefore weprovide a process for the preparation of the compounds of the generalFormula I above by oxidizing an o-amino azo dye of the general formula x-ca=cn- (where X has the above-stated meaning), and coupling theresultant diazotized compound with a compound of the formula H N--A,where A has the above-stated meaning. The intermediate compound may ifdesired be isolated before being coupled.

In order that the invention may be more fully understood the followingexamples are given by way of illustration only:

Example 1.2 (4" Styryl 3 Sulpho Phenyl) (Indaz0l04 :5 4 :5 -1 :2 :3-Triaz0le A solution of 16.32 parts of the sodium salt of 4-amino-stilbene-Z-sulphonic acid (91% pure) and 3.45 parts of sodiumnitrite in 150 parts of water is indirectly diazotized at 810 C. with 20parts of concentrated HCl. The diazo compound is isolated by filtration,suspended in Water and mixed with a solution of 6.7 parts ofS-aminoindazole in aqueous hydrochloric acid to effect coupling. The pHof the mixture is controlled .to 7-8 by addition of sodium acetateduring coupling. When the coupling is complete, the mixture is madealkaline by addition of sodium carbonate, and the sodium salt of theo-amino-azo dyestufi is salted out. The o-amino-azo dyestutf isdissolved in pyridine and refluxed for 3 hours with g. of coppersulphate and ml. of dilute ammonia, with ml. of water. On completion ofthe oxidation the product is precipitated by addition of hydrochloricacid. The crude product obtained is dissolved in dilute sodium carbonatesolution, boiled with sodium hydrosulphite and activated charcoal,screened and crystallized, giving a very pale yellow product having Amax. 352 m n.

This compound gives a vivid blue flourescence, and when a piece ofcotton, nylon or wool is washed in a detergent solution containing asmall amount of this compound, .the material acquires a much whiterappearance than before treatment.

Example 2.-2 (4" Styryl 3" Sulpho Phenyl) (Indazol0-6 7-4 :5) -1 :2:3-Triaz0le A solution of 16.32 parts of sodium salt of4-aminostilbene-Z-sulphonic acid (91% pure) and 3.45 parts of sodiumnitrite in 150 parts of water is indirectly diazotized at 8l0 C. with 20parts of concentrated HCl. The diazo compound is isolated, suspended inaqueous alcohol, and mixed with a solution of 6.7 parts of6-aminoindazole in acidified aqueous alcohol to effect coupling of thecomponents. The acidity of the mixture is controlled by addition ofsodium acetate during coupling. When the coupling is complete theo-amino-diazo dyestuff obtained is filtered off at 2530 C. Theo-amino-azo dyestuff is dissolved in aqueous alcohol and sodiumhydroxide and is oxidized by addition of an excess of sodium hydroxideand is oxidized by addition of an excess of sodium hypochlorite solutionadded dropwise at -75 C. On completion of the oxidation which is shownby the change of colour from red to orange the desired product obtainedis salted out. The compound is slurried with aqueous alcohol, madealkaline and treated With sodium hydrosulphite for a few hours at 70 C.to remove the last trace of coloured impurities. Finally, the compoundis recrystallized from aqueous alcohol. It has a x max. Of 353 I'D/L.

The compound so obtained is a greyish powder which in dilute solutiongives vivid blue fluorescence and when a piece of cotton is washed in adetergent solution containing a small amount of this compound thematerial acquires a much whiter appearance than before treatment.

A solution of 17.21 parts of the sodium salt of 4-amino- 4'-methoxystilbene-Z-sulphonic acid (95% pure) and 3.45 parts of sodium nitrite inparts of water is indirectly diazotized at 8-10 C. with 20 parts ofconcentrated HCl. The diazo compound is isolated, suspended in water andmixed wih a solution of 6.7 parts of 6-amino indazole in dilutehydrochloric acid to effect the coupling of the components. The acidityof the mixture is controlled by addition of sodium acetate duringcoupling.

5 When the coupling is complete the o-amino azo dyestuif is filtered offat 25-30 C.

The o-amino azo dyestulf is dissolved in pyridine and refluxed for 3hours with 30 parts of copper sulphate and 35 mls. of ammonia, with 60mls. of water. On completion of the oxidation the product isprecipitated by the addition of hydrochloric acid. The crude productobtained is dissolved in aqueous alcohol, made alkaline and treated withsodium hydrosulphite to remove the last trace of coloured impurities.The triazole crystallizes from the solution on cooling. It has A max.362 m A solution of 17.21 parts of the sodium salt of 4-amino-4'-methoxy stilbene-Z-sulphonic acid (95% pure) and 3.45 parts of sodiumnitrite in 150 parts of Water is indirectly diazotized at 8-l0 C. with20 parts of concentrated HCl. The diazo compound is isolated byfiltration, slurried in water and mixed with a solution of 6.7 parts of5-amino indazole in aqueous hydrochloric acid to effect the coupling ofthe components. The pH of the mixture is controlled to 7-8 by additionof sodium acetate during coupling. When coupling is complete, themixture is basified by addition of sodium carbonate and the sodium saltof the o-arnino azo dyestufi is salted out. The o-amino-azo dyestufi isdissovlved in water and refluxed for 3 hours with 30 parts of coppersulphate and 35 parts of ammonia, with 60 parts of water. After theoxidation the product is precipitated by addition of hydrochloric acid.The crude product obtained is dissolved in dilute alcoholic sodiumcarbonate solution boiled with sodium hydrosulphite and activatedcharcoal, screened and crystallized, giving a pale yellow solid, havingA max. 363 m Example 5.2-(4"-Styryl-3"-Sulph0 Phenyl) (1 MethylIndazl0-6 7'4 -1 :2 z3-Triaz0le A solution of 16.5 parts of sodium saltof 4-amino stil bene-Z-sulphonic acid (90% pure) and 3.45 parts ofsodium nitrite in 150 parts of water is indirectly diazotized at 8-10-C. with 20 parts of concentrated HCl. The diazo compound is isolated byfiltration, suspended in water and mixed with a solution of 7.35 partsof l-methyl- 6-amino indazole in dilute acid to etiect the coupling ofthe components. The pH of the mixture is controlled to 7-8 by additionof sodium acetate during coupling. When coupling is complete the mixtureis basified by addition of sodium carbonate and the sodium salt of theo-amino azo dyestuff is filtered at 25-30 C. The o-amino azo dyestufi isdissolved in pyridine and refluxed for 3 hours with 30 parts of coppersulphate and 35 parts of ammonia, with 60 parts of water. After theoxidation the product is precipitated by addition of hydrochloric acid.The crude triazole is recrystallized from 40% aqueous pyridine. It has Amax. 353 mu.

This is prepared exactly as in Example 5, replacing 1-methy1-6-aminoindazole by 3-methyl-6-amino indazole. It has A max. 355 m Example7.2-(4-Styryl-3"-Sulpho Phenyl) (1,3- Dimethyl-Indazol0-6' 7'-4 :5 -1 :2:3-Triazole A solution of 16.5 parts of the sodium salt of 4-aminostilbene-Z-sulphonic acid (90% pure) and 3.45 parts of sodium nitrite in150 parts of water is indirectly diazotized at 8-10 C. with 20 parts ofconcentrated hydrochloric acid. The diazo compound is isolated byfiltration, suspended in water and mixed with a solution of 8.05 partsof 1,3-dimethyl-6-amino indazole in dilute acetic acid to effect thecoupling of the components. The pH of the mixture is controlled duringcoupling at 7-8 by the addition of sodium acetate solution. Whencoupling is complete the o-amino-azo dyestufl is filtered off at 25-30C.

The o-amino-azo dyestufi is dissolved in pyridine and refluxed for 3hours with 30 parts of copper sulphate and 35 parts of ammonia, with 60parts of water. After the oxidation the product is precipitated withhydrochloric acid. The crude product is recrystallized from 25% aqueouspyridine. It has A max. 355 mp.

A solution of 18.62 parts of the sodium salt of 4-chloro- 4-aminos-tilbene-Z-sulphonic acid (89% pure) and 3.45 parts of sodium nitritein parts of water is indirectly diazotized at 8-l0 C. with 20 parts ofconcentrated HCl. The diazo compound is isolated by filtration,suspended in water and mixed with a solution of 6.65 parts of 6- aminoindazole in dilute acid to effect the coupling of the components. The pHof the mixture is controlled at 7-8 during the coupling by the additionof sodium acetate. When coupling is complete the o-amino azo dyestutf isfiltered off at 25-30 C. The dyestuff is dissolved in pyridine andrefluxed for 3 hours with 30 par-ts of copper sulphate and 35 parts ofammonia, with 60 parts of water. After oxidation the product isprecipitated by the addition of hydrochloric acid. The crude product isrecrystallized from aqueous alcohol. It has A max. 354 m Example9.2(4"-(2"'-Chl0r0styryl)-3"-Sulph0 Phenyl) (Indazol0-6':7'-4 :5 )-1 :2:3-Triaz0le This is prepared as in Example 8, replacing 4-chloro-4-amino stilbene-Z-sulphonic acid by 2-chloro-4-amino-stilbene-Z-sulphonicacid. It has A max. 352 m Example 10.2 (4"-(4"-Chlorostyryl) -3"-SulphoPhenyl) (Indazolo-I' :5-4:5)-1 :2 :3-Triaz0le This is prepared as inExample 8, replacing 6-amino indazole by S-amino-indazole. 'It has Amax. 355 mp.

This is prepared as in Example 8, replacing 4-chloro- 4-aminostilbene-2-sulphonic acid by 2'-chloro-4-ann'nostilbene-Z-sulphonic acidand 6-amino-indazole by 5- amino-indazole. It has A max. 351 me.

Some examples of the use of the compounds according to the invention asoptical whitening agents are as follows:

Example (a).White wool is boiled for 30 minutes in a bath containing0.05 gm. of the compound obtained in Example No. 1, and 2 grams offormic acid per litre. The material thus obtained shows a much brighterand whiter appearance than Without this after-treatment. A good eifectcan also be obtained by washing the wool in a soap bath containing 0.05gram per litre of the above whitener.

Example (b).-Yellowish-white paper (due to ageing) is treated with asolution containing 0.05 gram per litre of the compound mentioned inExample No. 1. After rinsing and drying the paper shows a much whiterappearance.

Example (c).A piece of aged white poplin (slightly yellowish) is washedin a detergent solution containing 0.05 gram per litre of the compoundmentioned in Example No. 2. After rising and drying the material shows abrilliant white appearance.

It will be appreciated that although only compounds in which the groupsR are hydrogen and methyl groups and in wihch the groups X are hydrogen,methoxy or chloro have been exemplified in the foregoing examples, thenature of these groups is not restricted thereby. Thus, for example, itwill be clear to those skilled in the art that the groups R can be otherlower alkyl groups. Similarly the groups X can for example be any loweralkoxy groups and need not necessarily be a methoxy group. Othervariations will be apparent to those skilled in the art.

We claim: I 1. A compound selected from compounds of the formula:

X CH=CH N A G N X S0 11 the group consisting of l I @012 -NR and inwhich R is a member selected from the group consisting of a hydrogenatom and a lower alkyl group; and alkali-metal salts thereof.

2. 2-(4"-styryl-3"-sulpho phenyl) (indazo1o-4:5-4:5)- 1:2 3-triazole.

3. 2-(4"-styryl-3-sulpho phenyl) (indazo1o-6':7-4: 5 1 :2: 3-triazole.

4. 2-(4 (4"' methoxy styryl) 3" sulpho phenyl) (indazolo-6':7'-4: 5 )-1:2: 3 tr iazole.

5. 2-(4-styryl-3"-sulpho phenyl) (1'-methy1 indazolo-6:7'-4:5)-1:2:3-triaz0le.

6. 2-(4"-styryl-3"-sulpho phenyl) (3-rnethyl-indazolo- 6':7-4: 5)-1 :2:3-t1'iazole.

7. 2-(4-styryl-3"-sulpho phenyl) (1':3-dimethy1-indazolo-6' 7-4 5 -12:3-triaZo1e.

8. 2 (4"-(4"'-chloro styryl)-3"-sulpho phenyl) (inda- 2010-6 7-4:5 -1:2: 3-triazole.

9. 2(4"-(2' chlorostyryl)-3" -su1pho phenyl)(indazolo-6':7-4:5)-122:3-triazole.

Zweidler et a1. Mar. 5, 1957 Adams et a1 Mar. 15, 1960

1. A COMPOUND SELECTED FROM THE GROUP CONSISTING OF COMPOUNDS OF THEFORMULA: